Editing Water trough (section)

{{Short description|Device to fill steam locomotives}}
{{about|the steam locomotive usage|the trough used to provide drinking water for animals|Watering trough}}
[[File:NYC 999.jpg|thumb|[[New York Central Railroad]]'s ''[[Empire State Express]]'' takes on water from the track pan at [[Palatine, New York]], in 1905.]]

A '''water trough''' ([[British English|British]] terminology), or '''track pan''' ([[American English|American]] terminology), is a device to enable a [[steam locomotive]] to replenish its water supply while in motion. It consists of a long trough filled with water, lying between the rails. When a steam locomotive passes over the trough, a water scoop can be lowered, and the speed of forward motion forces water into the scoop, up the scoop pipe and into the tanks or [[tender (rail)|locomotive tender]].